Heretofore, it was possible to obtain the internal combination of the tape locking device of the type disclosed in U.S. Pat. No. 3,664,231. By attempting to turn the actuating knob, one could observe that certain of the external combination push buttons moved. It was further noted, that it was these same buttons, which were needed to be depressed to release the system.
This invention is concerned with eliminating any feed-back through internal linkages, and with the unauthorized obtaining of the internal combination of the subject locking device through such feed-back.